Removed unneeded comma in third line

challenges/8.2.User_Defined_Functions/lesson.md

@@ -2,7 +2,7 @@
 
 The keyword `def` introduces a function definition.  
 It must be followed by the function name and a parenthesized list of formal parameters (if any).  
-The statements that form the body of the function start at the next line, and must be indented.  
+The statements that form the body of the function start at the next line and must be indented.  
 After a function has been defined, it can be called by typing the function name immediately followed by parentheses that contain the function's arguments (if any).
 - https://docs.python.org/3/glossary.html#term-function
 - https://docs.python.org/3/glossary.html#term-parameter